Add configuration setting for disabling running tests in projects (only compile and publish)

[prolativ]

No description provided.

[SethTisue]

in the Scala 2 community build there are all sorts of variations on this: don't even compile the tests; compile them, but don't run them; run them but omit a few specific test sources; and all of these variations sometimes occur on a per-subproject as opposed to per-repo basis